Answer
$7m\sqrt {2n}$
Work Step by Step
Step 1: $\sqrt {7m}\times\sqrt {14mn}$
Step 2: $\sqrt {7m\times14mn}$
Step 3: $\sqrt {98m^{2}n}$
Step 4: $\sqrt {98}\times\sqrt {m^{2}}\times\sqrt n$
Step 5: $\sqrt {49\times2}\times m\times\sqrt n$
Step 6: $7\sqrt 2\times m\times\sqrt n$
Step 7: $7\times\sqrt 2\times m\times\sqrt n$
Step 8: $7m\sqrt {2n}$
